CN111592900B - Full-particle-size coal pyrolysis method, pyrolysis unit and graded dust removal pyrolysis system - Google Patents
Full-particle-size coal pyrolysis method, pyrolysis unit and graded dust removal pyrolysis system Download PDFInfo
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- CN111592900B CN111592900B CN202010458342.3A CN202010458342A CN111592900B CN 111592900 B CN111592900 B CN 111592900B CN 202010458342 A CN202010458342 A CN 202010458342A CN 111592900 B CN111592900 B CN 111592900B
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
- C10B53/00—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form
- C10B53/04—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form of powdered coal
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
- C10B57/00—Other carbonising or coking processes; Features of destructive distillation processes in general
Abstract
A full-particle-size coal pyrolysis method, a pyrolysis unit and a graded dust removal pyrolysis system are disclosed, wherein the full-particle-size coal pyrolysis unit comprises a sorting device, a pyrolysis furnace and a moving bed pyrolysis device; the sorting device is used for sorting the coal with the whole particle size into coal with a coarse particle size and coal with a fine particle size; the pyrolysis furnace is used for carrying out solid heat carrier pyrolysis on the fine-particle-size coal sorted by the sorting device to obtain pyrolysis gas; a moving bed pyrolysis apparatus comprising: the indirect heat exchange pyrolysis section is positioned above and used for performing indirect heat exchange pyrolysis on the coarse-grain-size coal sorted by the sorting device; and the gas heat carrier pyrolysis section is positioned below and used for performing gas heat carrier pyrolysis on the coarse-particle-size coal from the indirect heat exchange pyrolysis section by using the pyrolysis gas as a gas heat carrier. The invention adopts the solid heat carrier to carry out pyrolysis on the pulverized coal, adopts the combination of indirect heat exchange and the gas heat carrier to carry out pyrolysis on the coal with the coarse grain diameter, and is beneficial to the lightening of tar and the improvement of the tar yield.
Description
Technical Field
The invention belongs to the technical field of coal pyrolysis, and particularly relates to a full-particle-size coal pyrolysis method, a pyrolysis unit and a graded dust removal pyrolysis system.
Background
The low-rank coal pyrolysis technology can convert substances with high chemical activity in coal into liquid fuels and chemicals, and is one of approaches for realizing clean and efficient gradient utilization of low-rank coal. Wherein tar is one of the main products of pyrolysis technology. In the prior art, a pyrolysis technology system using lump coal as a raw material has high thermal efficiency, good tar quality and low tar dust content, but has low tar yield, and the technology can not effectively utilize a large amount of pulverized coal generated by mechanized coal mining and does not meet the actual condition that the yield of the pulverized coal in China is about 70% of the total coal mining amount. Therefore, various pulverized coal pyrolysis technologies are developed in the prior art, and the pulverized coal pyrolysis technologies are divided into direct heating and indirect heating according to heating modes; the method can be divided into a gas heat carrier, a solid heat carrier, a heat storage type and the like according to the heat carrier mode. Although various pulverized coal pyrolysis technologies are developed and most pyrolysis technologies are subjected to pilot test, the problems of low tar yield, high tar dust content, unstable operation, low system thermal efficiency and the like generally exist.
The pulverized coal solid heat carrier pyrolysis technology has the advantages of high tar yield, high overall energy efficiency, easiness in coupling with other technologies and the like, but the pulverized coal pyrolysis technology generally has the problems of high tar dust content, poor tar quality and the like; after scale-up, the solid heat carrier is mixed with pulverized coal and heat is transferred, and the amount and temperature of the solid heat carrier are difficult to control. The prior art adopts various dust removal technologies to solve the problem of high dust content of tar, such as a high-temperature cyclone separator, particle bed filtration, high-temperature electrostatic dust removal, oil spraying and the like, but various technologies also have the problems of poor dust removal effect, blockage, great tar loss and the like. For example, some studies adopt dry raw coal as a particle layer filtering raw material to remove dust from pulverized coal pyrolysis oil gas, but due to the low temperature and fine particle size of the dry raw coal, tar is easily separated out in a contact area between the hot gas and the raw coal, which results in blockage.
Disclosure of Invention
In view of the above, the present invention is directed to a full-size coal pyrolysis method, a pyrolysis unit and a staged dust-removal pyrolysis system, so as to at least partially solve at least one of the above-mentioned technical problems.
In order to achieve the purpose, the technical scheme of the invention is as follows:
as one aspect of the present invention, there is provided a full particle size coal pyrolysis unit comprising a sorting unit, a pyrolysis furnace, and a moving bed pyrolysis unit; wherein the content of the first and second substances,
the sorting device is used for sorting the coal with the full particle size into coal with a coarse particle size and coal with a fine particle size;
the pyrolysis furnace is used for carrying out solid heat carrier pyrolysis on the fine-particle-size coal sorted by the sorting device to obtain pyrolysis gas;
a moving bed pyrolysis apparatus comprising:
the indirect heat exchange pyrolysis section is positioned above and used for performing indirect heat exchange pyrolysis on the coarse-grain-size coal sorted by the sorting device;
and the gas heat carrier pyrolysis section is positioned below and used for performing gas heat carrier pyrolysis on the coarse-particle-size coal from the indirect heat exchange pyrolysis section by using the pyrolysis gas as a gas heat carrier.
As another aspect of the present invention, there is also provided a full-size coal classification dust removal pyrolysis system, comprising:
a full-particle size coal pyrolysis unit as described above;
the pyrolysis gas separator comprises a pyrolysis gas separator inlet and a pyrolysis gas separator outlet, the pyrolysis gas separator inlet is connected with the pyrolysis furnace, and the pyrolysis gas separator outlet is connected with a gas heat carrier pyrolysis section of the moving bed pyrolysis device;
the pyrolysis gas separator is used for preliminarily removing dust from pyrolysis gas discharged by the pyrolysis furnace; and the coarse-particle-size coal in the moving bed pyrolysis device forms a coarse-particle-size coal moving bed with the gas heat carrier pyrolysis section in the indirect heat exchange pyrolysis section, and the coarse-particle-size coal moving bed finely removes dust from the primarily-removed pyrolysis gas.
As still another aspect of the present invention, there is also provided a full-particle size coal pyrolysis method implemented by using the full-particle size coal pyrolysis unit as described above, comprising the steps of:
separating the full-particle-size coal serving as a pyrolysis raw material into coarse-particle-size coal and fine-particle-size coal by using a separation device;
performing solid heat carrier pyrolysis on the fine-particle-size coal in a pyrolysis furnace to obtain pyrolysis gas;
and sequentially carrying out indirect heat exchange pyrolysis on the coal with the coarse particle size and carrying out gas heat carrier pyrolysis by taking the pyrolysis gas as a gas heat carrier in a moving bed pyrolysis device to finish the pyrolysis of the coal with the full particle size.
Based on the technical scheme, compared with the prior art, the invention has at least one or one part of the following beneficial effects:
the invention pyrolyzes the coal with full particle size, the coal with full particle size is separated into coal with coarse particle size and coal with fine particle size by using a separation device, the coal with fine particle size is directly pyrolyzed by a solid heat carrier in a pyrolysis furnace, the coal with coarse particle size is taken as a dedusting medium of a particle bed, pyrolysis gas generated by pyrolyzing the coal with solid heat carrier is used for pre-pyrolysis of slow pyrolysis of the coal with coarse particle size, thereby not only preventing pyrolysis volatile components from being blocked due to tar condensation when meeting cold particles, but also utilizing the waste heat of pyrolyzing the coal with solid heat carrier, and leading the pyrolysis of the coarse particles to be slowly pyrolyzed under a hydrogen-rich atmosphere, being beneficial to the lightening of tar and improving the yield of the tar;
the invention adopts a grading dust removal scheme, removes dust through a pyrolysis gas separator and a coarse-particle-size coal moving bed, performs coarse dust removal and fine dust removal on fine powder carried by pyrolysis gas, and solves the problem of high dust content of pulverized coal pyrolysis tar;
according to the invention, the interference air is introduced into the gas-solid separator and the vertical connecting pipe of the material returning device, so that the fine powder brought by the solid heat carrier is reduced, and the three-stage dust removal effect is realized by combining the coarse dust removal and the fine dust removal which are realized by the pyrolysis gas separator and the coarse-grain-size coal moving bed;
the gasification furnace adopts a three-level air distribution scheme, so that the temperature and the circulation quantity of the solid heat carrier can be well controlled, and the effects of controlling the pyrolysis temperature and the pyrolysis load are realized.
Drawings
FIG. 1 is a schematic diagram of a full-size coal pyrolysis unit and a full-size coal staged dust removal pyrolysis system according to an embodiment of the invention;
FIG. 2 is a schematic structural diagram of a material returning device of the pyrolysis furnace according to the embodiment of the invention;
FIG. 3 is a schematic cross-sectional view A-A of FIG. 2;
FIG. 4 is a schematic view of the inner side view of B in FIG. 2;
FIG. 5 is a schematic diagram of an integrated gas-solid separation and material returning device formed by a gas-solid separator and a material returning device according to an embodiment of the present invention;
FIG. 6 is a schematic cross-sectional view C-C of FIG. 5;
FIG. 7 is a schematic view of a turbulent air pipe tangentially inserted into a vertical pipe in the gas-solid separation and material returning integrated device in another embodiment of the present invention;
FIG. 8 is a schematic cross-sectional view taken along line D-D of FIG. 7;
FIG. 9 is a schematic view of the structure of a moving bed pyrolysis apparatus according to an embodiment of the present invention;
FIG. 10 is a schematic diagram of an indirect heat exchange pyrolysis section employing a shell and tube configuration according to an embodiment of the present invention.
In the above figures, the reference numerals have the following meanings:
1. a gasification furnace; 11. a primary air inlet; 12. a secondary air inlet; 13. a tertiary air inlet; 14. an outlet of the gasification furnace; 15. a solid heat carrier material returning port; 2. a gas-solid separator; 21. a gas-solid separator inlet; 22. a high-temperature coal gas outlet of the gas-solid separator; 23. a solid heat carrier outlet of the gas-solid separator; 3. a material returning device; 31. an inlet of a material returning device; 32. an outlet of the material returning device; 4. a pyrolysis furnace; 41. a solid heat carrier and a pulverized coal inlet; 42. a pyrolysis furnace solid heat carrier outlet; 43. a fluidizing gas inlet; 44. a pyrolysis gas outlet of the pyrolysis furnace; 45. a semicoke product outlet; 5. a material returning device of the pyrolysis furnace; 51. an inlet section; 52. an outlet pipe; 53. an annular striker plate; 54. a distributing device; 55. a descending section; 56. a horizontal segment; 57. a rising section; 6. a pyrolysis gas separator; 61. a pyrolysis gas separator inlet; 62. an outlet of the pyrolysis gas separator; 63. discharging the fine powder semi-coke; 7. a waste heat boiler; 71. an inlet of a waste heat boiler; 72. an outlet of the waste heat boiler; 8. a sorting device; 81. an inlet of a sorting device; 82. a first sorting device outlet; 83. an outlet of the second sorting device; 9. a moving bed pyrolysis unit; 9-1, an indirect heat exchange pyrolysis section; 9-2, a gas heat carrier pyrolysis section; 91. a pyrolysis gas inlet of a pyrolysis section of the gas heat carrier; 92. an inlet of the indirect heat exchange pyrolysis section; 93. a coarse semicoke outlet; 94. a pyrolysis gas outlet of the pyrolysis section of the gas heat carrier; 95. a heat source end inlet; 96. a heat source end outlet; 10. an oil-gas separation device; 101. an oil-gas separation device inlet; 102. a tar and water outlet; 103. a pyrolysis gas outlet of the oil-gas separation device; a. the1，A2，A3Is air; s, water vapor; c1A solid heat carrier; c2Fly ash; c3A semi-coke product; c4Fine powder carbocoal; c5Coarse semicoke; m1Pulverized coal; m2Coarse particle size coal; F. high-temperature coal gas; t, tar; w. pyrolysis water; g1A pyrolysis furnace fluidizing gas; g2Pyrolysis gas for removing tar and pyrolysis water.
Detailed Description
The existing pulverized coal pyrolysis technology generally has the problems of high dust content of tar, unstable operation, low system thermal efficiency and the like, and restricts the industrial popularization of the pulverized coal pyrolysis technology. On the other hand, the pulverized coal solid heat carrier technology adopting a low-speed bed as a pyrolysis chamber has the problems of uneven mixing of the solid heat carrier and pyrolysis raw materials and poor mass and heat transfer effects, so that a large pyrolysis chamber needs to be designed, and the scale amplification is not facilitated; and the solid heat carrier amount and temperature control are unstable, which results in unstable system operation.
In order to overcome at least one technical defect, the invention provides a full-particle-size coal grading dust removal pyrolysis system for pyrolyzing full-particle-size coal, the full-particle-size coal is separated into coarse-particle-size coal and fine-particle-size coal by using a separation device, the fine-particle-size coal is directly subjected to solid heat carrier pyrolysis in a pyrolysis furnace, the coarse-particle-size coal is used as a particle bed dust removal medium, pyrolysis gas generated by pyrolysis of solid heat carrier pulverized coal is used for pre-pyrolysis of slow pyrolysis of the coarse-particle-size coal, so that blockage caused by condensation of tar when pyrolysis volatile matter meets cold particles is avoided, waste heat generated by pyrolysis of the solid heat carrier pulverized coal is used, and the coarse-particle pyrolysis is performed at a low speed under a hydrogen-rich atmosphere, thereby being beneficial to tar lightening and improving tar yield.
In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.
As one aspect of the present invention, as shown in fig. 1, there is provided a full-particle-size coal pyrolysis unit including a sorting apparatus 8, a pyrolysis furnace 4, and a moving bed pyrolysis apparatus 9; wherein, the sorting device 8 is used for sorting the coal with the whole grain diameter into the coal with the coarse grain diameter and the coal with the fine grain diameter; the pyrolysis furnace 4 is used for performing solid heat carrier pyrolysis on the fine-particle-size coal sorted by the sorting device 8 to obtain pyrolysis gas; the moving bed pyrolysis apparatus 9, as shown in fig. 1 and 9, includes: the indirect heat exchange pyrolysis section 9-1 is positioned above and used for performing indirect heat exchange pyrolysis on the coarse-particle-size coal sorted by the sorting device 8; and the gas heat carrier pyrolysis section 9-2 positioned below is used for performing gas heat carrier pyrolysis on the coarse-particle-size coal from the indirect heat exchange pyrolysis section 9-1 by adopting pyrolysis gas as a gas heat carrier.
In the embodiment of the present invention, as shown in fig. 1, the sorting device 8 includes a sorting device inlet 81 as a raw coal inlet, a first sorting device outlet 82, and a second sorting device outlet 83, the first sorting device outlet 82 is connected to the solid heat carrier at the top of the pyrolysis furnace 4 and the pulverized coal inlet 41; the second separation device outlet 83 is connected to the indirect heat exchange pyrolysis section inlet 92 of the moving bed pyrolysis device 9.
More specifically, the sorting device 8 is used for sorting 0-30 mm raw coal (i.e., coal with a full particle size), and sorting the raw coal into pulverized coal (i.e., coal with a fine particle size) M1And coal M of coarse particle size2. Wherein, the pulverized coal M1The particle size of (A) is 0-6 mm, preferably 0-3 mm; pulverized coal M1A solid heat carrier and pulverized coal inlet 41 which is used as pyrolysis raw material of the pyrolysis furnace 4 and is conveyed to the pyrolysis furnace 4 from the first sorting device outlet 82; the remaining part of the raw coal, i.e., the coarse-particle-size coal M2The pyrolysis feedstock for the moving bed pyrolysis unit 9 is delivered from the second separation unit outlet 83 to the indirect heat exchange pyrolysis section inlet 92 of the moving bed pyrolysis unit 9.
In the embodiment of the present invention, as shown in FIG. 1, the pyrolysis furnace 4 is used for the pulverized coal M1The pyrolysis reaction is carried out, and a solid heat carrier and pulverized coal inlet 41 at the top, a pyrolysis gas outlet 44 of the pyrolysis furnace, a semicoke product outlet 45, a pyrolysis furnace solid heat carrier outlet 42 and a fluidizing gas inlet 43 are arranged. For strengthening solid heat carrier and powdered coal M1Mixing and transferring heat while avoiding a large amount of dust, in solid heat carriers and pulverized coal M1The location of entry into the pyrolysis furnace 4 (i.e., the interior of the pyrolysis furnace 4 directly below the solid heat carrier and pulverized coal inlet 41) provides a localized fluidization region. Pyrolysis gas G with partial removal of tar and pyrolysis water by means of pressurization2As fluidizing gas G for pyrolysis furnaces1. More specifically, the apparent wind velocity in the local fluidization region is 0.4m/s to 1.5m/s, and preferably 0.5m/s to 1 m/s.
In the embodiment of the present invention, as shown in fig. 1, the full particle size pyrolysis unit further includes a gasification furnace 1, the gasification furnace 1 is used for providing heat for the full particle size pyrolysis unit, the gasification furnace 1 is of a three-stage air distribution type, and is provided with a primary air inlet 11, a secondary air inlet 12, a tertiary air inlet 13, a gasification furnace outlet 14, and a solid heat carrier return port 15. The primary air gasifying agent conveyed by the primary air inlet 11 is water vapor S and air A1(ii) a The secondary air gasifying agent and the tertiary air gasifying agent respectively conveyed by the secondary air inlet 12 and the tertiary air inlet 13 are air A2，A3. The primary air inlet 11 is positioned at the bottom of the gasification furnace 1, the secondary air inlet 12 is positioned in a dense-phase region below the solid heat carrier return port 15, and the tertiary air inlet 13 is positioned at the middle upper part of the gasification furnace 1.
More specifically, the temperature and the amount of the solid heat carrier can be controlled by three-stage air distribution of the gasification furnace 1 and the semicoke product C discharged from the pyrolysis furnace 43The amount is adjusted. In the embodiment of the invention, the primary air gasifying agent accounts for 50-85% of the total amount of the gasifying agent, the secondary air gasifying agent accounts for 15-50% of the total amount of the gasifying agent, the tertiary air gasifying agent accounts for 0-15% of the total amount of the gasifying agent, preferably 5-10%, and the operating air speed of the gasification furnace 1 is 3-10 m/s, preferably 4-8 m/s.
Therefore, the gasification furnace 1 in the embodiment of the invention adopts a three-level air distribution scheme, so that the temperature and the circulation quantity of the solid heat carrier can be well controlled, and the effects of controlling the pyrolysis temperature and the pyrolysis load are realized.
In the embodiment of the present invention, as shown in fig. 1, the full particle size coal pyrolysis unit further includes a pyrolysis furnace return device 5, and the pyrolysis furnace return device 5 is used for returning the solid heat carrier of the pyrolysis furnace 4 to the gasification furnace 1. As shown in fig. 2-4, the pyrolysis furnace returning device 5 comprises an inlet section (i.e. inlet pipe) 51 and an outlet pipe 52, wherein one end of the outlet pipe 52 extends to the inside of the inlet section 51; an annular baffle plate 53 and a distributor 54 are respectively arranged up and down between the inlet section 51 and the outlet pipe 52.
In the embodiment of the invention, the pyrolysis furnace material returning device 5 is connected with the pyrolysis furnace solid heat carrier outlet 42 through the inlet section 51, the solid heat carrier entering the pyrolysis furnace material returning device 5 is uniformly distributed through the annular material baffle plate 53 and the distributor 54, and meanwhile, the gravity action of the solid heat carrier is decomposed, so that the influence of the material level height of the pyrolysis furnace 4 on the material returning quantity of the pyrolysis furnace material returning device 5 is eliminated.
This is because the solid heat carrier is distributed uniformly to each circumferential array of material returning units through the distributor 54, wherein the material returning units are a descending section 55, a horizontal section 56 and an ascending section 57 which are communicated with each other by the inlet section 51, the distributor 54 and the outlet pipe 52. It is worth mentioning that the material returning device 5 of the pyrolysis furnace includes, but is not limited to, 4-10 material returning units; preferably, 4-6 material returning units, such as 4 material returning units, are shown in fig. 3. The material returning units are isolated from each other, so that gas in the gasification furnace 1 is prevented from flowing into the pyrolysis furnace 4 through the space between the outlet pipe 52 and each material returning unit.
More preferably, the bottom of the descending section 55, the horizontal section 56 and the ascending section 57 of the material returning unit is provided with fluidized wind, and the material entering the descending section 57 is conveyed to the outlet pipe 52 by utilizing the gravity action of the material of the descending section 55 and the density difference between the material of the descending section 55 and the material of the ascending section 57. The material returning unit starts the material returning unit and adjusts the material returning amount of the material returning unit by starting fluidizing air and adjusting the fluidizing air quantity. So can realize the linear regulation of 5 returning charge volumes of pyrolysis oven returning charge device through the multiunit returning charge unit of evenly arranging, can enlarge 5 returning charge volume control limits of pyrolysis oven returning charge device through adjusting the fluidization amount of wind.
In order to improve the running stability of each material returning unit, the length-to-height ratio of the horizontal section 56 ranges from 2 to 10, and preferably ranges from 3 to 7. The ratio of the height of the rising section 57 to the equivalent diameter of the rising section 57 is in the range of 1.25 to 2.5.
In the preferred embodiment of the invention, the horizontal section 56 of the return device 5 of the pyrolysis furnace is added with transport wind in the same direction as the moving direction of the solid materials, so that the return capacity of a single return unit can be obviously improved. The wind speed range of the transported wind is 5-30 m/s. The ratio of the diameter of the air conveying pipe to the equivalent diameter of the horizontal section is 1/3-1/10.
As another aspect of the present invention, as shown in fig. 1, there is also provided a full-size coal staged dust removal pyrolysis system, comprising the full-size coal pyrolysis unit as described above;
the pyrolysis gas separator 6 comprises a pyrolysis gas separator inlet 61 and a pyrolysis gas separator outlet 62, the pyrolysis gas separator inlet 61 is connected with the pyrolysis furnace 4, and the pyrolysis gas separator outlet 62 is connected with the gas heat carrier pyrolysis section 9-2 of the moving bed pyrolysis device 9;
the pyrolysis gas separator 6 is used for preliminarily removing dust from the pyrolysis gas discharged from the pyrolysis furnace 4; coarse-particle-size coal in the moving bed pyrolysis device 9 forms a coarse-particle-size coal moving bed with the gas heat carrier pyrolysis section 9-2 in the indirect heat exchange pyrolysis section 9-1, and the coarse-particle-size coal moving bed finely removes dust from the primarily removed pyrolysis gas.
In the embodiment of the present invention, as shown in fig. 1, the system for graded dust removal and pyrolysis of full-grain-size coal further includes a gas-solid separator 2 and a material returning device 3, wherein an inlet 21 of the gas-solid separator 2 is connected to the gasification furnace 1 and is used for separating high-temperature coal gas from a solid heat carrier of the gasification furnace 1, and the gas-solid separator 2 is further provided with a high-temperature coal gas outlet 22 of the gas-solid separator and a solid heat carrier outlet 23 of the gas-solid separator; the return feeder 3 is used for conveying the solid heat carrier to the pyrolysis furnace 4 and preventing pyrolysis gas of the pyrolysis furnace 4 from flowing into the gas-solid separator 2, and is provided with a return feeder inlet 31 and a return feeder outlet 32.
In the embodiment of the invention, as shown in fig. 5 and 7, the gas-solid separator 2 and the return feeder 3 are designed as an integrated device, the return feeder inlet 31 is connected with the solid heat carrier outlet 23 of the gas-solid separator, and the return feeder outlet 32 is connected with the solid heat carrier and pulverized coal inlet 41. In order to reduce the solid heat carrier fine powder entering the pyrolysis furnace 4, as shown in fig. 6, the vertical pipe between the gas-solid separator 2 and the material returning device 3 is provided with interference air, the solid heat carrier particle size entering the pyrolysis furnace 4 is sorted, and the fine powder with the particle size less than or equal to 0.2mm is removed. More specifically, the apparent wind speed of the cross section gas at the position where the disturbance wind is introduced is 0.4-1.5 m/s; preferably, the apparent wind speed of the cross section gas at the position where the disturbance wind is introduced is 0.5m/s to 1 m/s.
In other embodiments of the present invention, the gas-solid separator 2 employs a cyclone separator; as shown in fig. 7 and 8, the gas-solid separator 2 and the material returning device 3 form a gas-solid separation material returning integrated device, an interference air inlet is arranged at the connection position of the bottom conical section of the gas-solid separator 2 and the vertical pipe of the material returning device 3, the interference air inlet of the vertical pipe is tangentially inserted into the interference air inlet of the turbulent air pipe, and the tangential direction of the interference air inlet is opposite to the tangential direction of the cyclone separator, so that a gas flow field opposite to the solid heat carrier flow field in the cyclone separator is formed, the cyclone separator flow field is more remarkably disturbed, and the regulation and control are more remarkable. The turbulent jet flow wind speed is the ratio of the turbulent flow wind quantity to the cross section area of the turbulent flow wind pipe, and the regulation range is 0-30 m/s.
In an embodiment of the invention, the pyrolysis gas separator 6 is a high efficiency cyclone.
In the embodiment of the present invention, the inlet velocity of the pyrolysis gas separator 6 ranges from 25m/s to 35 m/s.
In the embodiment of the invention, the waste heat boiler 7 and the moving bed pyrolysis device 9 form a high-temperature coal gas waste heat recovery unit, wherein the inlet 71 of the waste heat boiler 7 is connected with the high-temperature coal gas outlet 22 of the gas-solid separator, the outlet 72 of the waste heat boiler is connected with the inlet 95 of the heat source end of the moving bed pyrolysis device 9, that is, the heat source end of the indirect heat exchange pyrolysis section 9-1 is from the high-temperature coal gas F and the fly ash C from the outlet 72 of the waste heat boiler2. In addition, the heat absorption end comes from the coarse-particle-size coal M entering from the inlet 92 of the indirect heat exchange pyrolysis section of the moving bed pyrolysis device 92The two ends of the waste heat boiler are used for heat transfer through heat pipes, and the waste heat of the high-temperature coal gas at the outlet 72 of the waste heat boiler is applied to heating and pyrolysis of the coal with the coarse grain diameter. The gas heat carrier pyrolysis section 9-2 utilizes sensible heat of pyrolysis gas from the pyrolysis gas separator 6 to heat the coal M with the coarse particle size2Continuing to perform the coarse-particle-size coal M2Pyrolyzing; on the other hand, the coarse-particle-size coal M is used2The formed moving bed of the coal with the large particle size performs fine dust removal on pyrolysis gas from the pyrolysis gas separator 6. High temperature gas F and fly ash C2And the waste heat is discharged from a heat source end outlet 96 of the moving bed pyrolysis device 9 after heat exchange between the waste heat boiler 7 and the moving bed pyrolysis device 9.
It is worth mentioning that, as shown in fig. 9, in order to uniformly distribute air, shutter structures are adopted in the gas heat carrier pyrolysis section 9-2 corresponding to the gas heat carrier pyrolysis section pyrolysis gas inlet 91 and the gas heat carrier pyrolysis section pyrolysis gas outlet 94.
In other embodiments of the present invention, the heat exchange tubes of the indirect heat exchange pyrolysis section 9-1 of the moving bed pyrolysis apparatus 9 are not limited to the heat tube form, and the indirect heat exchange pyrolysis section 9-1 of the moving bed pyrolysis apparatus 9 may also be of a tube-and-shell structure, in which the high temperature flue gas passes through the tube side and the coarse-particle-size coal M is used2The structure of the shell pass (i.e. the heat exchange tube for the over-high temperature flue gas) is shown in fig. 10. The structure is simple, the manufacturing cost is low, and the replacement is easy. In order to avoid the dust accumulation in the heat exchange tube, the heat exchange tube is designed to be of a downward inclination structure, and as shown in figure 10, the included angle alpha between the central line of the heat exchange tube and the horizontal plane ranges from-10 degrees to-35 degrees.
In the embodiment of the invention, as shown in fig. 1, the full-particle-size coal grading, dedusting and pyrolysis system further includes an oil-gas separation device 10, wherein the oil-gas separation device 10 is provided with an oil-gas separation device inlet 101, a tar and water outlet 102, and an oil-gas separation device pyrolysis gas outlet 103. An inlet 101 of the oil-gas separation device is connected with a pyrolysis gas outlet 94 of a gas heat carrier pyrolysis section of the moving bed pyrolysis device 9, tar T and pyrolysis water W condensed in the oil-gas separation device 10 are discharged from a tar and water outlet 102, and pyrolysis gas G for removing the tar and the pyrolysis water2Discharged from a pyrolysis gas outlet 103 of the oil-gas separation device, wherein part of pyrolysis gas G for removing tar and pyrolysis water2After being pressurized, the mixture is used as the fluidized gas G of the pyrolysis furnace1。
As still another aspect of the present invention, there is also provided a full-particle size coal pyrolysis method implemented using a full-particle size coal pyrolysis unit, comprising the steps of:
sorting the full-size coal as a pyrolysis raw material into coarse-size coal and fine-size coal by using a sorting device 8;
performing solid heat carrier pyrolysis on the coal with the fine particle size in the pyrolysis furnace 4 to obtain pyrolysis gas;
and (3) carrying out indirect heat exchange pyrolysis on the coarse-particle-size coal and carrying out gas heat carrier pyrolysis by taking pyrolysis gas as a gas heat carrier in turn in the moving bed pyrolysis device 9 to finish the pyrolysis of the full-particle-size coal.
More specifically, in the embodiment of the invention, the solid heat carrier is adopted to carry out the treatment on the pulverized coal M1Performing pyrolysis, and performing indirect heat exchange on the coarse-grain-size coal M in a moving bed and gas heat carrier combination mode2Pyrolysis is carried out.
In the embodiment of the invention, as shown in fig. 1, a solid heat carrier circulation loop is formed by a gasification furnace 1, a gas-solid separator 2, a material returning device 3, a pyrolysis furnace 4 and a pyrolysis furnace material returning device 5 which are communicated in sequence, wherein an outlet pipe 52 of the pyrolysis furnace material returning device 5 is connected with a solid heat carrier material returning port 15 at the lower part of the gasification furnace 1.
In addition, it is worth mentioning that the invention removes dust in three stages aiming at the problem of high dust content of tar in the pulverized coal pyrolysis: in the first-stage dust removal, the vertical pipe between the gas-solid separator 2 and the material returning device 3 is provided with interference air, the particle size of the solid heat carrier entering the pyrolysis furnace 4 is sorted, fine powder with the particle size less than or equal to 0.2mm is removed, and the proportion of the fine powder in the solid heat carrier entering the pyrolysis furnace 4 is reduced; the second-stage dust removal is to carry out coarse dust removal on dust carried by pyrolysis gas through a pyrolysis gas separator 6; and the third-stage dust removal is used for fine dust removal of pyrolysis gas through a particle bed (namely a coarse-particle-size coal moving bed) formed by heated coarse-particle-size coal, and in order to ensure the dust removal effect and the stable operation of the particle bed formed by the coarse-particle-size coal, the pyrolysis temperature range of an indirect heat exchange pyrolysis section 9-1 of a moving bed pyrolysis device 9 is 360-550 ℃, the preferred temperature range is 400-500 ℃, and the pyrolysis temperature of a gas heat carrier pyrolysis section 9-2 is 550-600 ℃.
In conclusion, according to the characteristics of the coal pyrolysis process such as heating rate, temperature to particle crushing, volatile analysis, tar property and the like, the method adopts a segmented moving bed pyrolysis device to carry out pyrolysis on the coal with the coarse particle size. In the upper section, the coarse-grain-size coal is subjected to slow pyrolysis by adopting an indirect heat exchange pyrolysis mode with low heat transfer efficiency and low temperature rise rate, so that on one hand, fine powder is carried by volatile components due to the fact that a large amount of coarse particles are broken, and meanwhile, the surface temperature of the coarse particles is raised to the temperature at which tar is not condensed, and the surfaces of the coarse particles are modified. When the coarse particles enter the gas heat carrier pyrolysis section at the lower section, on one hand, the dust removal advantage of the particle moving bed can be fully exerted; meanwhile, the surface temperature of the particles is higher than the tar condensation temperature, so that the problem of blockage caused by condensation of volatile tar cannot occur; in addition, the continuous pyrolysis under the atmosphere of high-hydrogen-concentration volatile components is beneficial to improving the yield and the quality of the coarse particle pyrolysis tar.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (17)
1. A full-particle-size coal pyrolysis unit is characterized by comprising a sorting device, a pyrolysis furnace and a moving bed pyrolysis device; wherein the content of the first and second substances,
the sorting device is used for sorting the coal with the full particle size into coal with a coarse particle size and coal with a fine particle size;
the pyrolysis furnace is used for carrying out solid heat carrier pyrolysis on the fine-particle-size coal sorted by the sorting device to obtain pyrolysis gas;
a moving bed pyrolysis apparatus comprising:
the indirect heat exchange pyrolysis section is positioned above and used for performing indirect heat exchange pyrolysis on the coarse-grain-size coal sorted by the sorting device;
and the gas heat carrier pyrolysis section is positioned below and used for performing gas heat carrier pyrolysis on the coarse-particle-size coal from the indirect heat exchange pyrolysis section by using the pyrolysis gas as a gas heat carrier.
2. The full particle size coal pyrolysis unit of claim 1 wherein the pyrolysis furnace comprises a solid heat carrier and pulverized coal inlet at the top and a fluidizing gas inlet at the lower part for introducing fluidizing gas so that a local fluidizing zone is formed inside the pyrolysis furnace just below the solid heat carrier and pulverized coal inlet, and the apparent wind speed of the local fluidizing zone is 0.4m/s to 1.5 m/s.
3. The full particle size coal pyrolysis unit of claim 2 wherein the local fluidization region has a superficial wind velocity of 0.5m/s to 1 m/s.
4. The full-particle-size coal pyrolysis unit of claim 1, further comprising a gasification furnace, wherein the gasification furnace is of a three-stage air distribution type, and comprises a primary air inlet, a secondary air inlet, a tertiary air inlet and a solid heat carrier return port;
wherein, the primary air inlet is positioned at the bottom of the gasification furnace;
wherein, the secondary air inlet is positioned in a dense-phase region below a solid heat carrier return port of the gasification furnace;
wherein, the tertiary air inlet is positioned at the middle upper part of the gasification furnace;
wherein, the primary air gasifying agent conveyed by the primary air inlet comprises water vapor and air, wherein the primary air gasifying agent accounts for 50-85% of the total amount of the gasifying agent;
wherein, the overfire air gasifying agent conveyed by the overfire air inlet comprises air, wherein the overfire air gasifying agent accounts for 15 to 50 percent of the total amount of the gasifying agent;
the tertiary air gasifying agent conveyed by the tertiary air inlet comprises air, wherein the tertiary air gasifying agent accounts for 0-15% of the total amount of the gasifying agent;
wherein the operating wind speed of the gasification furnace is 3-10 m/s.
5. The full particle size coal pyrolysis unit of claim 4 wherein the tertiary air gasification agent is 5% to 10% of the total gasification agent.
6. The full particle size coal pyrolysis unit of claim 4 wherein the gasifier operates at a wind speed of 4 to 8 m/s.
7. The full-size coal pyrolysis unit of claim 4, further comprising a pyrolysis furnace return device for recycling a solid heat carrier of a pyrolysis furnace to the gasifier;
the material returning device of the pyrolysis furnace comprises an inlet pipe and an outlet pipe, wherein one end of the outlet pipe extends to the inside of the inlet pipe; an annular material baffle plate and a material distributor are respectively arranged between the inlet pipe and the outlet pipe from top to bottom;
a plurality of material returning units in a circumferential array are formed among the inlet pipe, the distributor and the outlet pipe and are used for realizing the linear adjustment of the material returning amount;
the material returning unit comprises a descending section, a horizontal section and an ascending section which are communicated with each other; wherein the length-to-height ratio of the horizontal section is 2-10; wherein the ratio of the height of the ascending section to the equivalent diameter of the ascending section is 1.25 to 2.5;
fluidized air is arranged at the bottoms of the descending section, the horizontal section and the ascending section and is used for realizing uniform distribution of the solid heat carrier;
the horizontal section is provided with an air conveying pipe for conveying air, and the air conveying pipe is used for outputting conveying air which is consistent with the moving direction of the solid materials in the material returning device of the pyrolysis furnace;
wherein the wind speed of the transportation wind is 5-30 m/s;
and the ratio of the diameter of the air conveying pipe to the equivalent diameter of the horizontal section is 1/3-1/10.
8. The full particle size coal pyrolysis unit of claim 7 wherein the horizontal section has a length to height ratio of 3 to 7.
9. The full particle size coal pyrolysis unit of claim 1,
the sorting device is used for sorting coal with a full particle size of 0-30 mm;
wherein the particle size of the fine particle size coal is 0-6 mm.
10. The full-particle-size coal pyrolysis unit of claim 9, wherein the fine-particle-size coal has a particle size of 0 to 3 mm.
11. The utility model provides a full particle size coal grading dust removal pyrolysis system which characterized in that includes:
a full particle size coal pyrolysis unit as recited in any one of claims 1 to 10;
the pyrolysis gas separator comprises a pyrolysis gas separator inlet and a pyrolysis gas separator outlet, the pyrolysis gas separator inlet is connected with the pyrolysis furnace, and the pyrolysis gas separator outlet is connected with a gas heat carrier pyrolysis section of the moving bed pyrolysis device;
the pyrolysis gas separator is used for preliminarily removing dust from pyrolysis gas discharged by the pyrolysis furnace; and the coarse-particle-size coal in the moving bed pyrolysis device forms a coarse-particle-size coal moving bed with the gas heat carrier pyrolysis section in the indirect heat exchange pyrolysis section, and the coarse-particle-size coal moving bed finely removes dust from the primarily-removed pyrolysis gas.
12. The system of claim 11, wherein the system further comprises a gas-solid separator and a material returning device,
the gas-solid separator comprises a gas-solid separator inlet, a gas-solid separator solid heat carrier outlet and a gas-solid separator high-temperature coal gas outlet; the inlet of the gas-solid separator is connected with the gasification furnace;
the gas-solid separator comprises a gas-solid separator and a gas-solid separator, wherein the gas-solid separator comprises a gas return device inlet and a gas return device outlet;
the material returning device is provided with an interference air inlet which is used for screening the solid heat carrier;
wherein, the interference air introduced from the interference air inlet is used for screening the solid heat carrier with the particle size less than or equal to 0.2 mm;
wherein the apparent wind speed of the cross section gas at the position where the interference wind is introduced is 0.4-1.5 m/s;
the full-particle-size coal grading, dedusting and pyrolyzing system further comprises a waste heat boiler, the waste heat boiler comprises a waste heat boiler inlet and a waste heat boiler outlet, and the waste heat boiler inlet is connected with the high-temperature coal gas outlet of the gas-solid separator;
a heat exchange tube for indirect heat transfer is arranged in the indirect heat exchange pyrolysis section, and an inlet of the heat exchange tube is connected with an outlet of the waste heat boiler;
the heat exchange tube is a heat tube or a tube-shell structure;
the heat exchange tube is of an inclined structure, and an included angle alpha between the central line of the heat exchange tube and the horizontal plane is-10 degrees to-35 degrees;
the full-particle-size coal grading, dedusting and pyrolysis system further comprises an oil-gas separation device, wherein the oil-gas separation device comprises an oil-gas separation device inlet, a tar and water outlet and an oil-gas separation device pyrolysis gas outlet; the inlet of the oil-gas separation device is connected with a pyrolysis gas outlet of a pyrolysis section of the gas heat carrier, and the pyrolysis gas outlet of the oil-gas separation device is connected with a fluidized gas inlet of the pyrolysis furnace.
13. The system of claim 12, wherein the cross-sectional gas apparent wind velocity at the position of the disturbance wind introduction is 0.5-1 m/s.
14. The system for graded dust removal and pyrolysis of full-particle-size coal as claimed in claim 12, wherein the gas-solid separator is integrated with a return feeder, and the conical bottom of the gas-solid separator is connected with a vertical pipe of the return feeder;
the interference air inlet is arranged at the joint of the conical bottom and the vertical pipe, and a turbulent air pipe is tangentially arranged at the interference air inlet;
the tangential direction of the turbulent air pipe is opposite to that of the gas-solid separator, and the turbulent air pipe is used for forming a gas flow field opposite to a solid heat carrier flow field in the gas-solid separator;
wherein, the ratio of the disturbed flow air volume of the disturbed air to the cross section area of the disturbed air pipe is defined as the disturbed flow jet flow speed, and the disturbed flow jet flow speed is 0 m/s-30 m/s.
15. The system of claim 11, wherein the pyrolysis temperature of the indirect heat exchange pyrolysis section is 360 ℃ to 550 ℃;
wherein the pyrolysis temperature of the pyrolysis section of the gas heat carrier is 550-600 ℃;
wherein, gaseous heat carrier pyrolysis section includes gaseous heat carrier pyrolysis section pyrolysis gas import and gaseous heat carrier pyrolysis section pyrolysis gas export inside the correspondence of gaseous heat carrier pyrolysis section pyrolysis gas import and gaseous heat carrier pyrolysis section pyrolysis gas export position set up the shutter structure respectively.
16. The full-size coal staged dust removal pyrolysis system of claim 15,
the pyrolysis temperature of the indirect heat exchange pyrolysis section is 400-500 ℃.
17. A full particle size coal pyrolysis process carried out using the full particle size coal pyrolysis unit of any one of claims 1 to 10, comprising the steps of:
separating the full-particle-size coal serving as a pyrolysis raw material into coarse-particle-size coal and fine-particle-size coal by using a separation device;
performing solid heat carrier pyrolysis on the fine-particle-size coal in a pyrolysis furnace to obtain pyrolysis gas;
and sequentially carrying out indirect heat exchange pyrolysis on the coal with the coarse particle size and carrying out gas heat carrier pyrolysis by taking the pyrolysis gas as a gas heat carrier in a moving bed pyrolysis device to finish the pyrolysis of the coal with the full particle size.
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